Gas turbine combined lubricating, and fuel supply system having centrifugal means topurify and circulate fuel



c. HILL 2,676,458

TING AND FUEL SUPPLY SYSTEM IFUGAL MEANS To PURIFY AND CIRCULATE F April 27, 1954 GAS TURBINE C HAVING CENTR Filed Sept.

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Patented Apr. 27, 1954 elenca SYSTEMi HfYINGGENe'- rammelen To Azmicmc tinnwtelawami..

by:refrencezto its'fannlication: inV sucl'rv engines; iti

slouldilie =understoodithat"the-invention in varie ous respects wisenut necessarily limited" thereto;y

Oneoffthe cliieadvantages.r of gas; turbinea engine., overarecinrocating; types" is its: compara:-V tively" small"sizexandligilitweight: Anotheris:its relative simpliei'ty'andfeaserof maintenance". The presentinvention.istaimed*generally` at Widening" the' margin ofadvantageqaofftlie gast turbine engine t particularlyirr these; andi otheru respects? I Specicalmf it is: an; objctz of" this invention to'u reduce complexit 1 ;weiglijt and-icost oi? the gas` turbinez' engineq byea" systenrrof lubricatinifwhiclr eflectivelyc eliminates'H previous:u oil; cooling; preh-A lemsr 'necessitatin-g` separate ol' cooling; plum inggtem'gerature ccntrol' and; How controlequigment; y

Y related 'Objectis-a' system* of*lubrication` vire tually eliminating; 01:5atlea'slr4 greatlyr'redcing; warm-upgtime-ofsucli1- engines:y

An'othermlvjectv.iswtorelirninateuse'ciiexpensive lubricatingoils int sucnenginesandtherebyre` diicethe needs' of*"frequent"service"inspectionsrzandf maintenance` operations"having;` to: dorwitlr add and* ciianginggof" lubricant Still another i object; of tlfie-` invention iszazsys'-f temi of lubricating gasr turbine engines. Wliereirr a *seriousrediictionw orf'ailure" oflbricat'ion: prese.- sure-v will beiaccomganiedautomatically '"byg reif` duction or failureof* fuelfsupplyfpressurezpso damagetoengine bearingsiis"preventiecl'a1fin:ii1tlier= attendant; rediiction` orw loss of power# Willi tewee-` outvvard* WarningA off: diliiau'ltiesr-aifectinga om tionV ofI tlief'engine: v

Still. another object, a -siiznpliiied andicomipactlyfarrangefiapparatns'operableftoipumpmand.. cleantheL engine:l'irlri'cantvr anrlfuel wlili'e lv funcf-a toningf'- alsoA asP a.' conduitf for distributing? the@ same toiv engine kiear-iri'glsc anni'l burner-sg respect-s tively; relatedeoljectfiis conn-:actiligflitfweiglitt apparatusf' offi suchv a; nature housed'f oit-income poratediiwi-thlnfexistingsrotatingcpartsroii thfeierii-fgine# to bei.4 rotatecli'operativelwtlierebyf `anni?` aiiuv to;saveetheespaceandiiimtirot addedibyfsepaa'ate Dumpingsfamifcleaningadeviceei:

of' :negaratusf4 internalto ashaft" foi" eiciently cleaning: Dumping'and distributinglubricant to` the shaft bearings for` lubrication thereof during rotatioir. oisuclr` shaft:-

Still* anotherv object is:l lubricant: cli-:ailingn ap*- paratus adapted for incorgoration compactly within` arotating; elementv andL foiconvenient removal- :fromsuchelementi-in; order toremovev sedim'ezit*amifcreign1 material' trappedffinside-the cleaning; device.

With these and otherf objects in View; they invention p iovidesfat lubricating? system' forgas turbine engines broadly; contemplating?- use of" the*enginefuelf;alsoasitlreflubrcantt; Tlieliquidf fuel? whether: kerosene.-y or an fuel; oil;y contained* im thei fuell tank: isf" deIiVeredLrQnr suclr tanktlirougii' common` or` trunk channels `from'V which it" isy distributed?v to the burnersarret4 lulcr'rcateciV bearings' t-lirougli"`4 appropriate lc'ra'ncli` connecitions.-

singief booster pumpv and* associated pressure:L relief' valve= supp-lying: fuel oil' under pressur the enginef serveA the: combined funcitions". o fuer and" lubricant deliverymeans;v

therebyjjeliminatng the. usual duplication of f; components"v for lubrication: purposes;-

imi-

purtantf{aldvajinzaget of" the vsystem utilizingo fuel asl the; lubricanirand" comprisingcommon: glimp-Y ingg anrldsributing* channelsV` therefor" resides in; the greater 'protection of the`4 engine; bearingsl it against burn-outcaused by; failure' offlubricantA pressure;A as. fuel.vx pressure0 must`V necessarily fail` at the` same time:A Such; anA` advantage` is not found ordinaryvengineswherein separatersystemsy offluhricamionv require;separatel p umps and separateI controlsf'whicli may fail' independently off one= another:

AfterN bleing; used" as*v lubricant the` fueloil-' isl caughtw inu theA engine' sump and@ returnecr' by a. scavengercpumptoetlies-fuelftanktmmixfwitlithe for-1f gas:-tmliinm enginesarey relatively-f large; on' tlieefueliii'wfiiecmently:replenislied tiieitempera ture rise -in tlief-tankrcaused bylieatfrejection from# the:1 engin-eV through the returned-ffiuel oillubrican willi not-ble cbj eetionablyfgreat: Thus` Amadditional@oliiect:.isctliprcvisiongeneralitaA e special?? apparatusi: internal?" tot thefengine foncleaning, pumping and distributing lubricant to engine bearings and the burners. A tubular member mounted inside a hollow compressor shaft receives the fuel oil from the booster pump and by rotating with the shaft acts as a centrifuge forming a core of pure fuel oil in the vicinity of its axis while solid particles and foreign matter are forced outward centrifugally trapped along the periphery of the tube. Radial tap pipes located at the shaft bearings communicate through the tube wall between its core region and the bearing interfaces. Such tap pipes likewise rotating at the tremendous speed of the i compressor shaft function as individual centrifugal pumps forcing the pure vfuel oil from the'v core region of the tubular-'member outwardly into the bearings for lubrication-fand cooling thereof. A separate inbuilt centrifugal pump formed directly in the hub assembly of the coinpressor drive forces pure fuel oil from the core region of the cleaner tube for delivery as lfuel to the burners.

features; objects and The foregoing and other advantages of the invention including certain details of construction of itsjpreferred, illustrative form will become more fully evident in the following description referring to' the accompanying drawing.I

Figure'l is a schematic diagramv proved lubricating system.

Figure 2 is ya longitudinal. sectional view of the engine illustrating certain"details of the apparatus incorporating additional features of the invention.

Referring rst to various features of a gas turbine engine employing the invention, thepo'wer'output section of the eng-ine includes a power output shaft (Figure l) the power output gear box I2 and the main power gee .l bine engine lubricatedin acc` rdance 'withthe im- Figure 2 which illustrates' vstarter-generator unit B3, booster and scavenger pumps (not shown) and other auxiliary componentsz Triangularly arranged web plates 82 bridge between the frame members TG to stiffen the frame as a symmetrical structure capable of resisting vibrational and torque vdisplacement, tendenoies.

Referring to both figures, the principal parts of the engine requiring lubrication include the three compressor shaft bearings 59, 5l and 52, and rotating elements supported by and within the power, output gear unit I2. The bearings and 52 are received in journalsll and 53, respectively, carried by. a sleeve 84 in the fra-ine of the gasproducing "section of the engine. A journal 55 supported by the partition structure 86 carries the bearing 5l. These bearings areillustrated as plain sleeve-in-collarv bearings to permit larger shaft diameters and reduced bearing costs, although "it lwill'be understood that the particular type offbearing' used in the engine is no part of this invention. The auxiliary component drive gearing 99 inside the requires lubrication, and preferably receives its turbine wheel I4 which drives the shaft through.

the gear unit I2.

The' gas-producingsection of the engine generally comprises the air compressor I6, the first-stage turbine I B drivingthe air compressor by means of the .shaft 2th e nozzle box 22, burner ducts (not shown), interconnecting the nozzle box and the air compressor, and the 'various auxiliary components and mount 2B therefon At the head en d ofthe engine air is admitted into the compressor It througha throat 28, and

by centrifugal pumping actioof thevaned wheel `A the n annular. collector chamber.L The compressed air is conducted from the- 3G, is driven into 32.

collector chamber fintoburner ducts (not shown). The not gases of combustion pass into' the turbine nozzle box 22 extending annularly around the'hub l -I 8 mounted on compressor of the turbine wheel shaft 29. Such gases then flow generally parallel to the turbine axis through 4turbinen'ozzles 36 directed against the blades of the nrst-stage turbine i8. Power thus generated-` drives the air compressorwheel 39 by meansv of the shaft 20. The hot gases passing I8 next pass through aseeond set of turbine nozmary turbine I4, beforepassing out through exthe blades of turbine wheel 65,v zles 3l for direction against the blades of the pri-f,

loil, kerosene or other lubricant. .in, the same manner and through branch',. connections similar to those associatedwith the output gear un1t1I2 as will. be described'.

In accordance with thel'present'invention fuel |99 isv pumped and both as the lubricant and burner fuel'. This common'cnannel includes the conduit H12, the booster pump Idil in such conduit and by-passed by the pressure relief valve l, and special purifying and pumping apparatus, generally designated |08, located internally of the compressor shaft ,20. By this internally mounted special apparatus, as described hereinafter particular reference to Figure 2, the fuel oil is purified, pumped and distributed to the bearings 59, 5l and 52, to the power output gear unit I2 and to the burners I lf3. A speed control unit I I2 of suitable form'. is interposed in the fuel supply lir'iejl'fs IUS to 'permit adjusting and controlling the speed and power of the engine. All lubricated bearings andpartsare connected for drainage into the engine sump IUI. return conduit H3 in the sump back into the fuel tank return conduit as shown.

A conduit 'IG branching from theconduit |02 delivers fuel-lubricant at booster pump pressure to the power output gear unit I2, wherein the lubricant is purified -by centrifugal separator delivers the heated lubricant means associated with the shaft of turbine I4 similar to centrifugal separator Ill, before being delivered to the bearings in such gear unit.

In such a system engine and bearing friction partition structure als liquidfueiiri tne'riiel tank delivered 'through a common... or .trunkv channel tov the engine for distribution in greater detail by i between the A burners and the apparatus A scavenger pump H6 in the through suchl rise until the heat .losses in the lines and :tank to gather with the heat carried `bach inteA lthe engine with :the fuel balance the amount of heat selected by the engine through the lubricant. .As previeusly mentioned, since the fuel tanks for gas, turbine engines will be relativelyrlarge or the f-uel frequently replenished, and further since the heat rejection `from suchen engine is relatively small, the `temperature Aof fuel-lubricant leaving the tank and delivered baci: to the engine for use as lubricant will not rise beyond :acceptable limits for "such a lubricant. The improved lubricating system therefore does away with the usual oil coolercommon to all engines of conventional type and thereby saves weight, space Aand cost. an.- other advantage of the improved system, `is Ythe saving of avpump, piping and new con-tml equipment ordinarily required for 'the `separate `'lubrication system in conventional engines.

The various considerations involved in the 'lubri'cation and supply of fuel to gas turbine engines are resolved favorably to the combina-tien of 'functions in the present system. Fuel oil, -for instance, having a lower viscosity than ordinary lubricating oils, is better able to act as a bearing coolant, yet adequately lubricates as well .in the case of the instant system because of the very high speed `and light loading of the rotating turbine parts. Moreover, with light fuel oil as the lubricant, the pressure of lubrication need not be as great as with the heavier oils; hence the improved system provides satisfactory vlubrication even at the lower pressure (about to-30 pounds per square inch)` under which the lubricant-fuel is delivered to the burners, as desired.

A particularly important advantage in such a system is the resulting protection-against possible bearing destruction through 'failure of lubricant pressure. When lubricant pressure fails for some reason such as failure of the booster pump i011, stickingof the pressure relief valve lultv in open position, or blockage in the common or trunk channel including conduit m2, for instance, the supply of fuel'under pressure to the burners l l0 Will also necessarily have failed because of the reliance upon a common lubricant and fuel supply channel. rIvhus the eng-ine will slow down orstop altogether and the attendant outward indications will be a suil'icient notice te the operator of functional difliculties. Thus the usual inconvenience and uncertainties of maintaining a constant watch over lubricant Vpressure byreference -to a meter or gauge are thereby overcome;

The lubricant-fuel is delivered into the engine through a demountable hollow receptacle unit 40 (Figure 2) mounted at the hub of the compressor wheel in alignment with the shaft 20. The hollowy compressor shaft 20 receives an elongated dirt collector or separator tube 42 extending substantially throughout the full length of such shaft. The left-hand end of` this elongated tube or liner sleeve carries an inlet nozzle 44` which entersk the receptacle to admit lubricant there. from intol the interior of the tube. The tube is appropriately tted. or otherwise secured inside theeeinpressor shaft 20 se that it rotates there.

with. as it does so at the high` speed of the shaft;

Z0, the fuel-lubricant in the tube is4 subjectedto. centrifugal 4force- Theheavy foreign elements,

including dirt, sludeesand undesired impurities in the liquid are subjected to a higher centrifugal force than the lighter pure liquid, hence are crowded outward against they inside periphery of' the tube '112l Whiletthe pure liquid remains in `the core region of .such tube. is true throughs cated far enough Afrom the inlet end of the tube that .centrifugal .forces have had .sume-lent `cpportunity to effect aseparat'ioncf. impurities frein the oil during Vits. generally axial flow along the tube. An annular .duct 4.6' formed around the tube 42 at the location of the .tap pipe 45 acts fas. a vcollecter duct which receives the lubricant passing outward through such pipe. Such lubricant next .passes outward through a plurality of cir,-

curnferentially spaced Yradial bores tl -in the shaft.

2-0 into .the bearing interface for lubrication and cooling thereof. The open inner `end of'zthe tapv pipe 46, terminating in the vicinityof thelongi--. tudinal axis of 'the shaft. 20, .draws off only the purined lubricant Yin the cere region .of tube .412..

ecause the pipe Mi is rotating at shaft speed, it functions as a centrifugal pump forcing lu bricant into. .duct 4.6.", and for Athe same reason. radial bores 4i! in shaft .213. also. actascentrifugal pumps. The supplemental pumping 'action .thus afforded at the tremendous rotational speeds normal in gas turbine engines (in the vicinity of 36,000 R. P. M.) insures adequate lubricating pressure 'for bearing 5G. The Abear-ing 52 is sim-4 ilarly vlubricated by the associated tapv pipe 233, collector duct a8 and radial bores 49 in theshaft wall at the location of such bearing.

The end of the compressorshaft `2=0 mounting' turbine i8 is journaled in a `combined thrust bearing and centrifugal pump. The end flange 2G of the shaftZ. has an annular rib 65 extending around its outer periphery. This ribv .con-V stitutes the shaft locating or retaining element ofV the thrust bearing assembly, being clamped between antifriction bearing rings including .the segmented ring E-T' on one rendy Aof such rib and the ring 5| on the opposite side thereof, both such rings being retained Within the xed suppnrting journal or collarv 55, as shown. Suitable sealsand spacer elements, including the end seal Tl', and the spacer ring T3, are kemployed as. shown .-in v:the drawing. The side of the ring 5l oppesite the rib is spherically rounded and engages .a com-` plementally rounded face formed inside the col. lar 55. I

A centrifugal pump formed in the foregoing hub assembly of turbine I8v comprises a pluralA ityof radial bores 64, extending through the muv tually overlapping turbine stub shaft t3', coni-Vv pressor shaftv flange .20' and the ribv 55 on such flange. .A central axial bore 60 in the end' closure 58 of separator tube 45 admits pure lubricant in the core region vof such tube into the inlet 62 vof the centrifugal pump, whereinit enters the inner ends of the radial bores 64. An annular collector duct ES., vformediin the journal collar 55, surrounds thel annular `thrust-bearing rib e5, to receive the fuel-lubricant pumped centri'fugally outward in such radial bores for delivery to. an outletconduit 68. The .passages between Lthe con-Vf duit 68 and the collector duct 65 are indicated by dotted lines in Figure 2. Pressure of the liquidv in the collector duct 6.6 causes seepage thereof through the interface regions of the. bearing ele. ments 5l, 61, 65 and 55' for lubrication and .coole` ing thereof.

The advantage in termsof simplicityand cornel 7, pactness of combining the elements of a thrust bearing with those of a centrifugal lubricant-fuel pump in the hub assembly of the turbine I8 will be evident. Moreover, locating the bores 64 in the existing larger-diameter or ribbed portion 65 of the shaft ange 20' enables maximum output pressure from the centrifugal pump thus formed to be attained, as such pressure is proportional to the radial extent of such bores.

Moreover, the convenience and other advantages of conducting and purifying the lubricantfuel inside the hollow compressor shaft 20v for admission into the combined centrifugal pump and thrust bearing in the hub assembly of turbine I8 will likewise be evident. The space inside the compressor shaft necessary to accommodate the various purifying and pumping components described is already available because the need of a large and relatively stiff compressor shaft of minimum weight is met by a hollow, largediameter shaft.

When the centrifugal separator tube 42 requires cleaning, the receptacle unit 40 may be removed from position to permit withdrawing the tube 42 out of the interior of compressor shaft 20. The tube may then be cleaned with gasoline or other solvent. Because of the relatively large eifective trap space for collecting dirt inside tube 42, such cleaning operations need not be frequent.

The fuel shut-off valve in line 68 permits turning off the engine fuel supply without intern rupting the engine lubricant supply, so that no damage to the bearings will result while the rotating parts are coasting to a stop or during starting wind-up of the engine.

I claim as my invention:

l. A combined lubrication and fuel supply system for an internal combustion turbine type engine, comprising in combination with a rotative hollow engine shaft having rotational support bearing means, a fuel tank, means conveying fuel from said tank to said engine shaft for admission Of such fuel into the shaft interior as a combined conduit and centrifugal purifier of fuel, centrifugal pump means comprising a pump passage extending generally radially of said shaft for rotation therewith at the bearing means location, said pump means passage having a fuel inlet disposed near the shaft axis for drawing purified fuel from the shaft interior and a fuel outlet ejecting such purified fuel into said bearing as lubricant therefor, a second centrifugal pump means comprising a pump passage extending generally radially of said shaft for rotation therewith, said latter pump means passage having a fuel inlet disposed near the shaft axis for drawing purified fuel from the shaft interior and a fuel outlet, and conduit means communicating with said latter outlet for delivering fuel pumped therefrom to the engine combustion chamber.

2. The system defined in claim 1, wherein the rotational support bearing means is located intermediate the ends of the shaft and the corresponding centrifugal pump means comprises a radial duct extending through a side opening in said shaft into the interior of the bearing, said duct being carried by an elongated tubular member extending lengthwise inside the shaft to rotate therewith.

3. The system dened in claim 2, wherein the fuel is admitted into the shaft interior at one end thereof, and the second centrifugal pump means is located at the end of the shaft opposite the fuel admission end thereof, whereby maximumV centrifugal purification of fuel is achieved by travelling the entire length of the rotating shafts interior before reaching such second pump means.

4. In a gas turbine engine, in combination with a hollow compressor shaft having bearings rotationally supporting the same at different locations along the length thereof, lubricating apparatus comprising an axially extending centrifuge duct removably received in the interior of the engines compressor shaft and rotative with such shaft, closure means in one end of said duct having a central opening therein to admit liquid lubricant into the same, said shaft having side openings therein at the respective locations of said shaft bearings, a plurality of generally radial conduit elements carried rotationally by said duct at the respective locations of such shaft bearings, each such conduit element having an open inner end disposed in the vicinity of the shafts axis to admit substantially pure lubricant therefrom and an open outer end in communication with a corresponding shaft side opening, to force such pure lubricant outwardly through such side openings into the respective bearings by centrifugal pumping action of said conduit elements during rotation of the shaft,

the centrifuge action in said duct forcing heavyA impurities in the lubricant outwardly to be trapped along the inside peripheral wall of such duct, and centrifugal pump means at the opposite end of the shaft and driven operatively thereby, centrifugal pump inlet means admitting purified liquid lubricant thereto from the central region of the shaft duct, and centrifugal pump outlet means connected to supply such lubricant to the engine burners as fuel.

5. The gas turbine engine lubricating apparatus defined in claim 4, wherein the centrifugal pump means is formed in the compressor shaft drive turbine hub assembly and comprises a radially apertured annular flange formed on the end of such compressor shaft and a radially apertured turbine stub shaft fitted into said flange and having an axial opening affording communication from the end of such stub shaft into its radial apertures, hence into those of said flange, for admitting liquid lubricant into the same to be pumped centrifugally by rotation thereof.

6. Apparatus for lubricating hollow shafts bearings, comprising a hollow rotative shaft and a plurality of bearings rotatively supporting the same at different locations along the length thereof, a tubular member removably received 4 inside the shaft and extending lengthwise thereof along and past said bearing locations to rotate with said shaft about a common central axis, closure means at one end of said tubular member having an axial inlet therein to admit liquid lubricant into said tubular member, a plurality of generally radial open-ended conduit elements at the respective bearing locations, carried by said tubular member to project inwardly thereof to the vicinity of said axis and rotate with such member, the wall of said shaft having a plurality of apertures formed therein at locations within the respective bearings for passage of lubricant from the conduit elements outwardly through said apertures into such bearings, rotation of said shaft and tubular member producing centrifuge action on the lubricant within such member to centralize purified lubricant therein along its axis for tapping by said conduit elements, and rotation of such conduit elements with said tubular :member producing 'centrifugal pumping @action nf fs'uch purified ,lubricant by said conduit :elements out .into `the bearings, the conduit :elementm'earestsaid inlet being vset iapart materially `therefrom to permit separation of impurities from the lubricant centrifugally before 'reaching and entering such `conduit element by ygenerally axial fiow through said tubular member, and combined centrifugal pump and thrust bearing means on the shaft comprising a thrust :bearing annular rib extending around and fixed to the shafts outer periphery and having therein a plurality of generally radial lubricant passages extending through the shaft to inner ends located in the vicinity of the shafts axis, means admitting pure lubricant from a substantially axial location inside the shaft into the inner ends of said latter lubricant passages for centrifugally pumping such lubricant outwardly through such passages, fixed collar means encircling said annular rib and defining a lubricant collector space therearound, and thrust bearing rings retained inside said collar means adjacent opposite sides, respectively, of said rib and having thrust surfaces engaging the same, such surfaces being lubricated by lubricant forced centrifugally outwardly through said passages into said collector duct and seeping therefrom between such surfaces and the rib surfaces engaged thereby.

7. Apparatus for lubricating hollow shafts bearings, comprising a hollow rotative shaft and a plurality of bearings rotatively supporting the same at different locations along the length thereof, a tubular member removably received inside the shaft and extending lengthwise thereof along and past said bearing locations to rotate with said shaft about a common central axis, closure means at one end of said tubular member having an axial inlet therein to admit liquid lubricant into said tubular member, a plurality of generally radial open-ended conduit elements at the respective bearing locations, carried by said tubular member to project inwardly thereof to the vicinity of said axis and rotate with such member, the wall of said shaft having a plurality of apertures formed therein at locations within the respective bearings for passage of lubricant from the conduit elements outwardly through said apertures into such bearings, rotation of said shaft and tubular member producing cen- I,

trifuge action on the lubricant within such member to centralize purified lubricant therein along its axis for tapping by said conduit elements, and rotation of such conduit elements with said tubular member producing centrifugal pumping action of such purified lubricant by said conduit elements out into the bearings, the conduit element nearest said inlet being set apart materially therefrom to permit separation of impurities from the lubricant centrifugally before reaching and entering such conduit element by generally axial fiow through said tubular member, shaftrotated centrifugal pump means mounted on the end of the shaft opposite the closure means and having an inlet drawing purified lubricant from the central region of the shafts interior, and conduit means conveying such lubricant pumped by said latter pump means to a location remote from said shaft.

8. Combined thrust bearing and centrifugal lubricant pump means for a hollow shaft, comprising means to admit liquid lubricant into the hollow interior of the shaft to be subjected to centrifuge action during shaft rotation, forcing lubricant impurities radially outward while form- `inge, score region of :relatively .pure lubricant in the vicinity of the shafts rotation axis, a thrust Shear-ing .fannular @rib .extending around v:and fixed to -the -shafts outeriperiphery and having therein a vplurality sof generally rradial lubricant passages :extending through the shaft to inner ends located in the vicinity iof lthe ishafts axis, means admitting pure lubricant from a substantially axial location :inside -the sha-ft into `the inner ends 0f Said fatter lubricant pas/ Sages for centrifugally pumping such lubricant outwardly 'through'such passages, fixed collar means encircling said 'annular rib vand ydefining 'a lubricant collector space therearound, and thrust bearing rings retained inside said collar means adjacent opposite sides, respectively, of said rib and having thrust surfaces engaging the same, such surfaces being lubricated by lubricant forced centrifugally outwardly through said passages into said collector duct and seeping therefrom between such surfaces and the rib surfaces engaged thereby.

9. A fuel supply system for an internal combustion turbine type engine, comprising in combination with a rotative hollow engine shaft having a rotational support bearing means, a fuel tank, means conveying fuel from said tank to said engine sha-ft for admission of such fuel into the shaft interior as a combined conduit and centrifugal purifier of fuel, centrifugal pump means comprising a Dump passage extending generally radially of said shaft for rotation therewith located remotely along said shaft from the admission point of fuel therein, said pump means passage having a fuel inlet disposed near the shaft axis for drawing puried fuel from the shaft interior and a fuel outlet, and conduit means communicating with said latter outlet for delivering fuel pumped therefrom to the engine combustion chamber.

10. The system defined in claim 9, wherein the fuel is admitted into the shaft interior at one end. thereof, and the centrifugal pump means is located at the end of the shaft opposite the fuel admission end thereof, whereby substantially the entire length of such shaft interior constitutes a centrifugal separator and collector of fuel impurities.

ll. A combined lubrication and fuel supply system for an internal combustion turbine type engine, comprising in combination with a rotative hollow engine shaft having a plurality of rotational support bearings at different locations along the length thereof, a fuel tank, means conveying fuel from said tank to one end of said engine shaft for admission of such fuel into the rotative shafts interior as a combined conduit and centrifugal purifier of fuel, centrifugal pump means each comprising a pump passage extending generally radially of said shaft at the respective bearing locations foi` rotation with said shaft, said pump means passages each having a fuel inlet disposed near the shaft axis for drawing purified fuel from the shaft interior and a fuel outlet through the side of the shaft ejecting such purified fuel into the respective bearings as lubricant-therefor, further centrifugal pump means having a pump passage extending generally radially of said shaft for rotation therewith, said latter pump means comprising a generally radially extending pump passage rotative with said shaft and having a fuel inlet disposed near the shaft axis for drawing purified fuel from the shaft interior and a fuel outlet, and conduit means communicating with said latter outlet for delivering 1 1 fuel pumped therefrom to the eugine combustion chamber.

12. The system dened in claim 11, wherein the shaft has a bearing located at the position along the shaft of the latter centrifugal pump means adapted to receive, as lubricant, a portion of the purified fuel pumped thereby.

References Cited in the le of this patent UNITED STATES PATENTS j Number Name Date 1,674,191 Chilton June 19. 192s Number w Number Name Date Cattaneo June 2,1931 Carvelli Aug. 30, 1932 Bernard Jan. 5, 1937 Planiol et al Feb. 20, 1945 Thompson June 18, 1946 Storey May 10, 1949 FOREIGN PATENTS Country Date France Oct. 21, 1935 

